calculation of non-adiabatic coupling terms between the ground x²a1 and first excited a²b2 electronic states of no2 molecule

In the present work, the non-adiabatic coupling terms are investigated between the ground x²a1 and the first excited a²b2 electronic states of no2 molecule. at the first, the high-level quantum chemical method like casscf is applied to determine the conical intersection geometry between the ground and the first electronic states. the changes of non- adiabatic coupling terms with bond angular and bond length are computed by molpro program. the calculations have been carried out in three contours around one atom. finally the conversion of adiabatic to diabatic angle have been calculated for this molecule